iCal - Incorrect Language via Exchange

I have an odd problem. When creating calendar entries for my work account on iCal, the invitations, changes, and cancellation notices all come through in German. For instance, I just created a calendar entry for Dec 25 and here's what came through on the invitation:

Zeit: Dienstag, 25. Dezember 2012 12:00-13:00. (UTC-05:00) Eastern Time (USA, Kanada)

Using my same account, and creating an entry using Outlook Webmail, everything works properly in my native English. Similarly, if I create a calendar invitation using my iPhone or iPad, everything is in English. It is just via iCal.

Further, I added my calendar to my wife's MacBook Air and created a test cal entry. That too came through in German. So I am pretty convinced that there is an iCal issue somewhere.

I've checked with my company's IT group, and they insist everything is set up properly for English on the back end.

I am on OS X 10.8.2 and all up to date on software updates.

Any ideas?